1. Field of the Invention
This invention relates to a device for draining liquid from a steam turbine, which is particularly suitable for use with a geothermal steam turbine utilizing wet steam.
2. Description of the Prior Art
Liquid droplets are inevitably generated in a steam turbine, especially in the lower pressure part. The droplets do not assist in driving the turbine, and they have a negative effect on efficiency. Moreover, the droplets cause erosion on rotating parts such as rotor blades. The problem is especially severe in the case of geothermal steam turbines because the original steam utilized has a high wetness content.
A conventional manner of draining liquid from a turbine is to discharge the liquid from different pressure stages of the turbine through orifices in the pipes. However, some of the steam is inevitably discharged with the liquid through the orifices, and this steam leakage obviously lowers the efficiency of the turbine. Moreover, impurities contained in the steam, such as FeS and FeS.sub.2, accumulate on the orifices, and the orifices are plugged during the operation of the steam turbine. It is a severe problem, especially in geothermal steam turbines because of the presence of large amounts of impurities in the steam.